With a wide range of potential applications, Machine Type Communication (MTC) or Machine to Machine (M2M) communication is gaining a tremendous interest among mobile network operators, equipment vendors, MTC specialist companies, and research bodies. The idea of M2M communications is to enable M2M components to be interconnected, networked, and controlled remotely with low-cost scalable and reliable technologies. M2M communication could be carried over mobile networks (e.g. GSM-GPRS, CDMA EVDO networks). In the M2M communication, the role of mobile network is largely confined to serve as a transport network.
An M2M device is capable of replying to request for data contained within those devices or capable of transmitting data autonomously. Sensors and communication devices are the endpoints of M2M applications.
Triggering of MTC devices is based on the use of an identifier identifying the MTC device that needs to be triggered. The MTC device trigger is used by the network to wake up the device, e.g., to initiate communications. A services capability server/application server (SCS/AS) may use a device trigger to send information to the user equipment (UE) via the third generation partnership project (3GPP) network to trigger the UE to perform application specific actions that include initiating communication with the services capability server (SCS) for the indirect model or an application server (AS) in the network for the hybrid model.
However, a UE may become temporarily unavailable to receive trigger messages, e.g., when the UE is out of coverage or is resource constrained, when the UE runs out of storage space, etc. In such cases, the network stores or en-queues the undelivered trigger messages for the same UE and re-attempts delivery at a later stage if the trigger validity period has not expired. Nevertheless, when a trigger is queued for delivery, the trigger may no longer be necessary or the trigger message itself may become redundant or irrelevant. For example, a stored trigger message that requests the UE to send smart meter billing data for 10 minutes may later be ineffective because 20 minutes of smart meter billing data may now be requested. A stored trigger message that requests the UE to establish a user plane communication link may become obsolete if the trigger message is queued for too long. Also, the SCS/AS may lose the context for the device trigger while the device trigger is queued. Further, if unnecessary triggers are delivered, then network resources are wasted and the network becomes inefficient.